Comprehensive Geophysical Measurement in Seismic Safety Evaluation: A Case Study of East Lake High-Tech Development Zone, China

Abstract

Wuhan East Lake High-tech Development Zone is a National Innovation Demonstration Zone where several major projects are under construction. For the seismic safety evaluation of the zone, it is urgent to find out basic data such as stratigraphic structure, geometric characteristics of buried faults, and overburden thickness. In this study, seismic reflection and microtremor surveys are adopted in seismic safety evaluation in urban areas for the first time. Combined with borehole data, the overburden thickness and buried faults in the target area are detected and analyzed. The results are as follows: ① The seismic reflection detection is carried out for the possible hidden locations of the Xiangfan-Guangji Fault and Macheng-Tuanfeng Fault in the target area, and the obtained high-resolution seismic reflection profiles can be used to precisely divide the stratigraphic structure and preliminarily find out the geometric characteristics such as the strike, tendency, and the buried depth of the upper breakpoint of the buried faults. ② A microtremor survey is carried out in key regions of the target area, and the obtained velocity structure imaging can provide a perspective window into the urban underground space structure and accurately determine overburden thickness and the depth of strongly and moderately weathered bedrock. Comprehensive geophysical measurements can better realize the acquisition of basic data such as the stratigraphic structure of complex regions and characteristics of urban buried faults, which provides an important basis for seismic fortification. At the same time, the combined application of geophysical methods avoids the detection of the blind area and provides a guarantee for urban safety and sustainable development. Furthermore, the study has reference value for seismic safety evaluation in similar areas of the world. If comprehensive geophysical measurement can be popularized, its economic and scientific value will be immeasurable.